This invention relates to an embossed, decorative sheet-type covering material and to a method for preparing such material.
Decorative sheet-type covering materials, such as vinyl floor coverings, are well known in the art and various attempts have previously been made to impart three-dimensional textured characteristics to the surface of such materials. For instance, U.S. Pat. No. 3,458,337 to Rugg suggests a method for producing a textured surface by employing a resin layer containing a catalyst activated foaming agent and then applying in selected pattern areas an agent for suppressing the catalytic action of the catalyst. Canadian Pat. No. 930,920 suggests a method for obtaining see through embossings in resinous foam products by the use of large amounts of inhibitors to completely inhibit foaming in selected areas of a resinous foam layer. Mechanical embossing, as taught for instance by U.S. Pat. Nos. 3,655,312 and 3,741,851 to Erb and Maass, has also been used to obtain three-dimensional textured surfaces. The disclosures of the above-mentioned U.S. patents are incorporated herein by reference.
Unfortunately, none of the known prior art techniques has proven entirely satisfactory. This has been especially true in situations wherein various special effects such as the see through effects described in the above-mentioned Canadian Pat. No. 930,920 are desired. The method of chemical inhibition described in the above-mentioned Canadian patent is not always entirely satisfactory from a production standpoint because, for successful use of that process, it is essential that foaming of the plastic be completely inhibited in the embossed areas. This requires a high concentration of inhibitor resulting in production difficulties since either multiple in register applications or thick inhibitor coating deposits such as silk screen deposits are necessary to prevent foaming. Also, use of chemical inhibition to prevent foaming and produce transparent or see through embossings presents additional inherent problems in that the foams used are limited to chemically blown foams and because of the critical nature of the inhibitor-catalyst-blowing agent relationships, the foam formulation is somewhat restricted and critical.